The present invention relates to a lower vehicle-body structure of an automotive vehicle in which an auxiliary device, such as a battery, is provided below a floor panel.
US Patent Application Publication No. 2015/0107921 A1 and Japanese Patent Laid-Open publication No. H09-272400 are known as the structure in which the auxiliary device, such as the battery, is provided below the floor panel. The first patent document discloses the structure in which a battery module as the auxiliary device is provided below the floor panel in an area which is enclosed by a floor flame and a tunnel frame (tunnel side member), which are respectively provided to extend in a longitudinal direction as a vehicle-body rigidity member at each side of right-and-left both sides of the floor panel, and front-and-rear seat cross members, which are respectively provided to extend in a vehicle width direction as the vehicle-body rigidity member.
That is, the battery module disclosed in the above-described first patent document is protected by being provided at the floor panel such that it is enclosed by the above-described vehicle-body rigidity members in a vehicle bottom view.
In the structure disclosed in the first patent document, however, since no vehicle-body rigidity member extending in the vehicle width direction is provided at a portion which corresponds to the battery module in the vehicle bottom view, such as a portion located below the battery module, there was still room for improvement in protection of the battery module against a vehicle side collision (side face collision) or the like.
The second patent document discloses the structure in which plural batteries as the auxiliary device are provided below the floor panel to extend in the vehicle width direction, a storage box which stores the batteries therein is attached so as to straddle a fixation portion (a tunnel portion), this battery storage box is composed of a roughly rectangular-shaped bottom portion which covers the batteries from below and a frame portion which is configured to rise upward from four sides of this bottom portion, and a whole part of the batteries provided below the floor panel are covered with the battery storage box from outside.
In the structure disclosed in the second patent document, however, while the protection performance of the batteries is improved because the batteries are protected with the hard storage box, there was room for improvement in achieving a light weight of a vehicle body.